[Objective] The aim was to investigate the dimer formation between the movement proteins(MP)in barely yellow dwarf virus by using the technology of bimolecular fluorescence complementation technology and to further study the relationship between MP homodimerization and viral movement.[Method] The DNA sequence of bimolecular fluorescent complementary vector containing cloning multiple cloning sites,35S promoter and terminator was cloned into the expression vector pCAMBIA1300,which replicates at a higher copy number in E.coli.Then,the BYDV-MP gene fragment was amplified in the presence of the whole BYDV-PAV cDNA sequence as template and the primers designed according to the BYDV-MP gene sequence from GenBank,cloned into the modified bimolecular fluorescent complementary vectors pCAMBIA1300-NE and pCAMBIA1300-CE.The resulting vectors were transformed into Agrobacterium by electroporation method and infiltrated into the tobacco leaf.Protein interactions were observed under fluorescence microscope.[Result] Yellow fluorescence could be viewed in the leaves co-infiltrated with Agrobacterium carrying pCAMBIA1300NE-MP and pCAMBIA1300CE-MP at 2-5 d post-infiltration,while yellow fluorescence could not be observed in negative control groups.[Conclusion] BYDV-MP formed homodimers in plant cells.The results can provide theoretical basis for further in-depth research about the movement process and mechanism of BYDV.